Andrej,
glTexImage3D is not a GLUT entry point, but rather is a standard GL 1.2
entry point. However, Windows uses GL 1.1, and only defines the 1.1
entry points in its system DLLs opengl32.dll and glu32.dll. Hence you
must use wglGetProcAddress to access glTexImage3D as a non-standard (on
1.1) entry point.
(The following example uses DrScheme 4.2 FFI syntax, for which I
apologize-- I have not tracked the changes in Racket 5.0 and beyond, nor
even had a chance to use it. I believe that the Racket FFI is pretty
similar to its ancestor. If not, then I apologize again for the on-list
noise, and hope that somebody else will chime in and correct me.)
First, we dynamically load wglGetProcAddress from the Windows
implementation of OpenGL:
(define wglGetProcAddress
(get-ffi-obj 'wglGetProcAddress (ffi-lib "opengl32") (_fun #:abi
'stdcall _string -> _fpointer)) )
Add a little sauce to convert the code address returned by that Windows
syscall into a Scheme procedure:
(define (gl-load-extension name ftype)
(let ((f (wglGetProcAddress name)))
(if f (ptr-ref f ftype) (lambda x (DIE-HORRIBLY)))))
(For (lambda x (DIE-HORRIBLY)), substitute the abend or log output of
your choice signaling the lack of the extension. (lambda x #f) works, too.)
Now we use this to access the implementation of glTexImage3D in your
video card's driver, assuming that the entry point exists therein:
(define glTexImage3D
(gl-load-extension "glTexImage3D"
(_fun #:abi 'stdcall _gl-enum _gl-int _gl-int _gl-sizei _gl-sizei
_gl-sizei _gl-int _gl-enum _gl-enum _gl-voidv ->) ))
And voila, there's your glTexImage3D procedure. (Or so I hope. To echo
Noel's caveat, the above is totally untested but Should Work.)
For further reading, please see the "FFI" chapter in the Racket
documentation. You will find it quite enlightening. The FFI is a
marvelous thing.
Good luck.
Ben
On 11/27/2010 11:08 AM, mosi wrote:
> Backup plan: is there a good book on MZScheme, FFI, dynamic loading of
> DLL functions ?
> [...]
> (glTexImage3D GL_TEXTURE_3D 0 3 width height depth 0
> GL_RGB GL_UNSIGNED_BYTE new-img-vec) ;; this is not
> supported in my Racket ! ? !